Feshbach resonances in an ultracold mixture of⁸⁷Rb and⁴⁰K

Abstract

We report the experimental preparations of the absolute ground states of 87 Rb and 40 K atoms (|F = 1, m F = 1 + |F = 9/2, m F = −9/2 ) by means of the radio-frequency and microwave adiabatic rapid passages, and the observation of magnetic Feshbach resonances in an ultracold mixture of bosonic 87 Rb and fermionic 40 K atoms between 0 T and 6.0 × 10 −2 T, including 7 homonuclear and 4 heteronuclear Feshbach resonances. The resonances are identified by the abrupt trap loss of atoms induced by the strong inelastic three-body collisions. These Feshbach resonances should enable the experimental control of interspecies interactions.

Observation of dipolar splittings in high-resolution atom-loss spectroscopy of Li6 p -wave Feshbach resonances

“…This non-degeneracy was predicted to give rise to a phase transition from a p x to a p x + ip y state in a p-wave superfluid (SF) [3], which plays an essential role in SF liquid 3 He [4] and neutron SFs inside neutron stars [5,6]. The dipolar splitting was observed in a spin-polarized gas of 40 K [1] and a large variety of quantum-gas mixtures [7][8][9][10][11]. It is attributed to effective spin-spin (ss) interactions including the magnetic dipole-dipole interaction and the secondorder spin-orbit coupling [2].…”

Radio-frequency spectroscopy of weakly bound molecules in ultracold Fermi gas

“…At the same time, we use a resonant laser beam for 30 µs to remove the 87 Rb atoms without losing and heating 40 K atoms. [14,15] Finally, we transfer 40 K atoms from the |F = 9/2, m F = 9/2 state to the |1 = |F = 9/2, m F = −9/2 state in a rapid adiabatic passage induced by sweeping an RF field across all the magnetic Zeeman states in F = 9/2 manifold in 50 ms, where the horizontal external magnetic field is about 19.6 G. [24] To create the bound molecules, the atoms in |1 state are transferred to a 50/50 mixture of |1 and |2 in higher magnetic field B = 203.6 G by RF of π/2 pulse. Then, we adiabatically ramp the external magnetic field from B 1 = 204 G at the BCS side to various final magnetic field values B 2 (201.1-201.6 G) at the BEC side of the resonance in 20 ms, and associate two free atoms into Feshbach molecules (see Fig.…”

Method of temperature compensation to spin-valve sensor based on PGA

“…However, when applied in a large range of temperature variation, a temperature compensation is needed to calibrate the output of the spin-valve sensors, in order to complete high precision measurement, such as smart meters, security systems. A very common method of temperature compensation is software-based compensation method [5], which establishes mathematical model for the output data of sensors, and analyzes and processes through a dedicated algorithm, ultimately realizes temperature compensation, such as least square method [6], particle swarm optimal algorithm [7], BP neural network algorithm [8]. But these methods have complicated calculation steps and need a long time optimization.…”